Usage of Ansoft/HFSS
simulation tool in mobile device
development
Jari Jekkonen
Content
• Commercial, non-commercial and in-house 3D EM tools used in NOKIA
• Development process of mobile phone
• Simulation goals
• Early verification of EM properties of the device
• Design check / validation
• Timing for simulations
• Sample models
• Discussion
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cost_presentation.ppt / 2005-12-13 / JJ
Commercial, non-commercial and in-house 3D EM
tools used in NOKIA
• Commercial
• Ansoft/HFSS (FEM)
• CST/MWS (FDTD/FIT)
• Flomerics/EMC/FLO (TLM)
• FEKO (MoM/FEM)
• IE3D (MoM)
• Non-commercial
• NEC (MoM)
• In-house
• Aplac – FDTD
• Boundary-element method by HUT
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Current status of the usage of the HFSS in NOKIA
• NOKIA wide EMC simulations network
• Re-use of simulation models (model library)
• Early verification by simulations
• started in some sites
• Part of the minimum block design process
• Iterative between mechanics, BB, RF and EMC
• NOKIA wide tool for EM simulations
• Import:
• Export
• SAT
• SAT
• STEP
• JPEG
• IGES
• GIF
• AutoCAD DXF
• BMP
• SLD
• TIFF
• GEO
• 3D modeller
• STL
• AutoCAD DXF
• VRML
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Development process of the mobile phone
• General steps of the mobile phone development
• M-steps are the maturity check points of the phone development
(technology maturity)
are prototype builds
P_
• E-steps are the execution points of product program (management level)
Product maturity steps
M0
M1
M2
M3
M4
M5
M6 M7
M8
M9 M10 M11
Pre-study / technology freeze
Technology implementation
production
Sale
Product builds
P2 P3 P4 P5 P6
P1
E-1
E0
E0.5
Project execution milestones
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E1
E1.5
E2
E3
E4
E5
M12
Early verification of EM properties of the device
Goals are
• to increase EM quality of the product
• to have less HW prototyping during the development project
-> Shorten design time
• Reduce testing time
• to produce design rules for following projects
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© 2005 Nokia
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Early verification of EM properties of the device
• IOP simulations
• Antenna simulations
• prototyping
• EM separation of antennas
• Noise coupling between BB parts and antennas
• E.g. Camera noise to GSM antenna
• Hinge simulations
• Conductive vs. non-conductive
• Surface material effects
• Optimum placement for sensitive components
• SIM
• MMC, SD, etc.
• Risk level estimation based on simulations
• Done already for couple of projects
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Isolation between GSM antenna and SIM lines
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Isolation between GSM antenna and display
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Design check / validation
• EMC measurements vs. simulations
• Model updates
• Re-use blocks to simulations library
• Shielding modifications
• E.g. SIM reader is designed by simulations for Gromit
• IOP measurements vs. simulations
• Antenna measurements vs. simulations
• Design updates
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© 2005 Nokia
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Timing for simulations
Pre-concept
simulation
Concept
simulations
Detection of
potential EMC
risks in whole
concept and
development of
general
simulation plan.
Draft test of
Check for
coupling
placement of
between parts
main blocks
and antenna
(antenna,
(model from
battery, SIM,
MMC, camera, other project is
used)
RF)
HFSS
M0
Calculation of the
near-field radiation
and detection of
hot spots on PWB
Second test of
coupling between
parts and antenna
HFSS,
SIWave
HFSS
HFSS
M1
First test
M2
M3
Verification with
available proto
EMC checks based on
calculation of 3-D analysis
of the EM field inside the
product
HFSS, SIWave
M4
M5
M6 M7
M8
M9 M10 M11
Pre-study / technology freeze
Technology implementation
production
Sale
B2 B3 B4 B5 B6
B1
E-1
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E0
E0.5
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E1
E1.5
E2
E3
E4
E5
M12
Pre-concept model
• Not very detailed model
• First draft for antenna solution
• Structural resonances
• Best places for sensitive
modules/components
concept level model
• More details
• Some component/module locations
are fixed
• Simulations for design help
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concept level model
• More details
Grounding points
• Some
component/module
locations are fixed
• Simulations for
design rules
Camera
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E-field 900MHz (GSM)
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E-field 1750MHz (GSM)
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E-field 1900MHz (GSM)
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E-field 1980MHz (WCDMA)
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First tests
• Detailed models for EM-parts
(connectors, memory card readers,
etc.)
• Working antenna model
• All shields and other conductive parts
fixed
• Firs EMC tests done and compared to
simulations
• Corrections for design (using
simulations)
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E & H-field 900MHz (GSM)
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E & H-field 900MHz (GSM)
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E & H-field 1750MHz (GSM)
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© 2005 Nokia
cost_presentation.ppt / 2005-12-13 / JJ
E & H-field 1750MHz (GSM)
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© 2005 Nokia
cost_presentation.ppt / 2005-12-13 / JJ
E & H-field 1900MHz (GSM)
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© 2005 Nokia
cost_presentation.ppt / 2005-12-13 / JJ
E & H-field 1900MHz (GSM)
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E & H-field 1980MHz (WCDMA)
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GSM900 (ver. 1)
Very critical area!
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GSM1800 (ver. 1)
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GSM1900 (ver. 1)
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GSM900 (ver. 2)
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GSM1800 (ver. 2)
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GSM1900 (ver. 2)
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cost_presentation.ppt / 2005-12-13 / JJ
Conclusions
Simulation
• tools are very useful from the very beginning of the design process
• can be used as a risk analysis tool of the EM environment of the product
• can be used to make prototyping with limitations
• may be used to produce design rules for daily engineering work
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Questions
?
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© 2005 Nokia
cost_presentation.ppt / 2005-12-13 / JJ